This proposal is to request support for a Keystone Symposia meeting entitled ?Intracellular and Intercellular Signaling in Dendritic Cell Function?, which will be held in Keystone, Colorado from February 25 ? March 2, 2007. The myriad of cellular interactions that ultimately regulate immune responses are mediated by specific ligandreceptor interactions that in turn trigger intracellular signaling pathways. Recent advances in basic cellular and molecular immunology have provided a framework for understanding how the immune response is initiated and regulated, integrating different[unreadable] cell types, molecules and signaling pathways.The Keystone meeting will focus on the immunomodulatory capacity of dendritic cells (DC), a critical cell type in immune regulation.[unreadable] [unreadable] Emphasis will be placed on:[unreadable] ? Receptors that play an important function in pathogen recognition by DC as well as receptors involved in DC processes such as cell adhesion, migration and signaling[unreadable] ? The potential role of activating and inhibitory ligands and receptors in modulating DC function[unreadable] ? The intracellular signaling triggered by these receptors and the mechanism by which they activate or inhibit immune effector functions as well as determine cellular lifespan[unreadable] ? The molecules involved in cross-talk between DC and other cells and tissues[unreadable] ? The mechanisms of DC interactions with the tumor microenvironment[unreadable] ? The DC regulatory pathways regulating immunity versus tolerance